Combined evaporator and boiler



Dec. 21, 1948. J. E.'POTTHARST, JR 2,456,732

COMBINED EVAPORATOR AND BOILER Filed Feb. 19, 1946 v 5 Sheets-Sheet 1 FIG. I

gi FIG43 4o L INVENTOR.

JOHN E. POTTHARST JR.

Dec. 21, 19486 J. E. POTTHARST, JR

COMBINED EVAPORATOR AND BOILER 3 Sheets-She'et 2 Filed Feb. 19, 1946 4 w LI FIGS i M B Q I I I IH l n m 4 .I W 9 I l P B Z I r 1 [t 1! I 5 I'll l I I I I I I I II I m 2 INVENTOR. JOHN E. POTTHARST JR :s Sheets$heet 5 Filed Feb. 19,. 1946 INVENTOR; JOHN E. POTTHARST JR.

Patented Dec. 21, 1948 UNITED STATES PATENT OFFICE COMBINED EVAPORATOR AND BOILER John E. lottharst, Jr., New Orleans, La. Application February 19, 1946, Serial No. 648,706

4 Claims. 1

My invention comprises certain new and useful improvements in evaporators.

In many types of evaporators it may be necessary to supply some amount of external heat to supplement the usual heating medium for evolving vapors from the solution to be evaporated.

In the accomplishment of this purpose in my invention I provide a unitary evaporator structure in which a liquid is boiled in out-of-contact heat exchange relation with hot gases and the vapors thus evolved are added to the principal supply of heating medium and brought into out-of-contact heat exchange relation with the solution supplied to the evaporator.

In the accompanying drawings, wherein I have illustrated a practical embodiment of the principles of my invention,

Fig. l is a top plan view of the evaporator;

Fig. 2 is a side elevation looking in the direction of the arrows in Fig. 1;

Fig. 3 is a view in horizontal section taken along the line 3-3 in Fig. 2;

Fig. 4 is a view in vertical section taken alon the line 4-4 in Fig. 1;

Fig. 5 is a view in vertical section taken along the line 5-5 in Fig. 1;

Fig. 6 is a view in vertical section taken along the line 66 in Fig. 1;

Fig. '7 is a view in horizontal section taken along the line 'l'l in Fig. 2, and

Fig. 8 is a view in horizontal section taken along the line 88 in Fig. 2.

Referring in detail to the drawings, Ill indicates the outer shell of the evaporator which is preferably cylindrical in shape, and which is closed at the top and bottom by the cover II and the bottom closure I2, respectively, which are preferably made removable so that access may be had to the tubes for cleaning. Any suitable means, not shown, are provided to seal the joints with the shell, such as gaskets.

I3 and I4 indicate, respectively, the upper and the lower tube sheets which are fixed, as by welding in the interior of the shell adjacent to but spaced from the ends of the latter. Both of said sheets are provided with substantially triangular openings cut therein, as indicated at l5, said openings being vertically aligned with each other. l6 indicates a vertical partition of substantially angular cross sectional shape, the horizontal edges of which are welded to the tube sheets around two sides of the openings [5, while the vertical edges of the partition are welded to the Wall of the shell. The openings l5 and the partition I 6 with the wall of the shell form the open ended downtake ll of the evaporator.

l8 indicates a partition of angular cross sectional shape, the top edge of which is welded to the under side of the lower tube sheet l4 and the vertical edges of which are weldedto the wall 2 of the shell. The lower edge of the partition is provided with a flat flange which fits against the bottom closure I 2 forming a sealed joint therewith. The partition I'B divides the space between the lower tube sheet and the bottom closure, into two chambers l9 and 20, the former being the solution admission chamber to which the solution to be evaporated is admitted by the pipe 2!, and. the other being a chamber into which hot gases such as the exhaust gases from an internal combustion engine are supplied by the pipe 22.

23 indicates a partition, similar in cross sectional shape to the partition l8, the lower edge of which is welded to the upper surface of the upper tube sheet l3 and the vertical edges of which are welded to the wall of the shell. The top edge of the partition 23 is provided with a flat flange which fits the under surface of the cover II and. has a sealed joint therewith. The two partitions l8 and 23 are vertically aligned with each other.

The partition 23 divides the space between the upper tube sheet and the cover into two chambers, the vapor chamber 24 and the hot gas chamber 25.

26 indicates a bank of vertical tubes having their opposite ends fixed in the tube holes in the upper and lower tube sheets and connecting the solution chamber IS with the vapor chamber 24. The space between the tube sheets through which the tubes 26 extend forms the solution heating chamber 21.

28 indicates a second bank of tubes which have their opposite ends fixed in the tube holes of the upper and lower tube sheets and connect the chambers 28 and 25 for the upward passage of hot gases. 2

29 indicates a baffle having the same cross sectional shape as that of the partition [8 and aligned therewith, the lower edge of the bafiie 29 being welded to the lower tube sheet while its vertical edges are welded to the wall of the shell, thus forming a chamber 36 into which a liquid is introduced through the pipe 3|. Preferably the baffle extends upwardly about three-fourths of the distance to the upper tube sheet, thus providing for a sufficient supply of pure liquid. The space between the top of the baffle 29 and the upper tube sheet provides communication between the chambers 30 and 21. 32 is a port in the cover H for the escape of spent gases from the chamber 25.

33 indicates a baffle depending in the downtake H, the cross sectional shape of which is angular with the vertical edges of the partition welded to the wall of the shell. At its upper end the bafile 33 is provided with a horizontal wall having an arcuate perimetral edge which fits against the wall of the shell and is welded thereto just below the top of the latter.

It will be observed that the baifie 33 divides the upper portion of the downtake 11 into two passages for the vapors, a passage 36 through which the vapors travel downwardly and a passage 31 through which the vapors travel upwardly to enter the=conduit:34.

34 indicates a vapor withdrawal conduit having its inner end extending upwardly within the space enclosed by the bailie 33.

Where steam is used as the principal heating medium in the heating chamber 27, the conduit 34 withdraws from the evaporator thevapors evolved from the solution in the tubes26 and conducts the same to a condenser *or'otherapparatus.

35 indicates a conduit leading to an" opening in the shell of the evaporator, which conduit, -tvheresteam is *em'plo'yedas the principal heatingm'edium conductssuch steam to the heat- "ing-chamber 21.

*W'herethe vapors are compressed and thecom- -pressedvapors-are to be used in the evaporator -as theprincipal-heating medium for the solution *in'th'e tubes'-' 26,"'the "conduit 34 is connected to the inletof the compressor' while the'conduit 35 is-con'nectd to"theoiitlet of the compressor.

38 indicates the constant =lev'el blowd'own' pipe the inta-ke end of which, preferably funnel -shape'dhi's positi'on'ed within the-d'owntake ll at the levlat-which the solution is tostarid in the "dow-ntake'and in the s'o'lutio'n' tu'bes 26. The dowh't-a'ke' leads *outthrou'gh the wall "of the stem- 5m.

'39- indicates the 'pipe for the withdrawal of the condensat fromthe chamber *2 l.

The-evaiporator is equipped with the usual ac- -ce'ssdries,--"-sudh" as the *clean o'ut connection 60, the drainplug '5 I, the liquid levelgauges' 22 and 42a; indic'atin'g, respecti-v'ely,' the levels of liquid in the chambers Q'T- and" 3 0 and the vents "'43 for the es'cape'of n'o'n-'conder-rse'd-or non-condens- --'able gas-es.

Pure liquidrsuch-as bf thesame'char'a'c'ter as the =-coridensate-produced by the ev'aporator, --is introduod thi'ough'the pi es l "iii-to the chamber sur- "roufilling the' -t'u bes 28,=-afid is' heal-ted and boiled by hot gases introduced from any selected-source through the pipe- 22' in'to the chamber and traveling up' through the tubes28 and escaping through'the 'chamber-" -a'nd outlet 32, causing l' t'he'zli'quid in the chamberte'fl to boil.

The steam from the boiling liquid -in the chamberfill and the' exc'ess liquid flow over the ibaiflle 2 9 into the heating chamber 2 l where they mingle :with the main heating medium and the :-conden'sate, and by outaoflcontact heat exchange sults in the condensation of the Vapors in said chamber, and the condensate is led off from the lower portion ofthe chamber 21 through the con- .densate removal pipe 39.

The elevation of the intake end of the blow- L down "38 determines the level of the solution in with the solution in the tubes-.26 cau'ses vapors to" be evolved from fthe solution, which vapors rise *into'the'vapor chamber 24, and pass into the upper end bhthecdowntake ll, first traveling downwardly through the passage 36 until they reach the lower end of the baflle 33 where the nvapors .abruptlyreverse theirdirection of travel and pass upwardly lin lthe. passage 31 and es- 'capeithrou'gh the conduit34. I

1. The:2abrup't reversal of travel-of the vapors as they pass around the lower end of the ba'flie results in the do'wnward discharge of such droplets of liquid which maybe entrained in the vapors.

Any suitable supply of hotgases to the chamber 20 and'the tubes 28 maybe employed. Thus.

for instance, hot gases from the combustion 0f '7 fuel may be "employed. "-In the case of the thermocompression operation, or in other operations wherein an internal combusion engine is employed, these gases convenientlymaybe the 'exhau'stgases of the engin'e.

the evaporator and withdraws concentrated solution therefrom.

I claim: 1. I-n an' evaporator thecombin'ation of I a shell, top and bottom cl'osuresfor the shell, a pair of 'tube sheets' fixed in the shell in spaced relation with each 6ther, andspaced 'from the closures,

the space between :the lower tube sheet and the bottom closure -be'ing divided "into a solution chai'n'ber'and-a lower hot gas chamber, and the spacebetweenthe upper tube sheet and the top closure b'eing divided into'a vapor chamber and "an upper hot gas 'ch'amber, a "bank of tubes having their-opposite ends securedin the tube holes in "said tube "sheets and connecting the solution chamber with the vapor chamber, a walled heating chamber through' 'whi'ch -said bank of tubes -'ex'-tend;a downtake connectingthe vapor chamher with the solution 'chamben' means for maintaining a supply of the solution to me evaporated in the s'olu't'ionchamber, 'in said bank of tubes "and-'in-said down-takea-second'bank of tubes having their ends secured in the tube holes of the tube sheets and connecting the hot gas chambers, an upwardly extending partition risin'g from thlower tube sheet and completing a liquid chamber through which the second bank of tube's'eXtends, means 'fo'r introducing hot gas into the lower hot gas chamber to travel upwardly through the second bank of tubes, means for supplying a second liquid to s'aidliquid chamber t'o be *boileti by' '-the hot gases; the evolved steam flowing into the heating chamber, means for conducting offthe vapors evolved from the solution in the first bank of tubesgmeans for withdrawing excess sblution' 'from the downtake, and means for withdrawing the condensate from "the-heating chamber.

2. The structure of claim 1 characterized by "theprovision-of means forseparating the droplets o'f 'solut'ion from the "vapors during their travel from the first bank of tubes to the downtake.

3. A'unitary evaporator'structure comprising an outer enclosure, a bank of tubes in which a supply o'fthe solution to be "evaporated is main- 'tained,'*-a heating chaihber "through which said tubes extendfa second bank of "tubes extending through said chamber "and through-which tubes hot gases are I caused to travel, "a' baffle extending upwardly from' the -'fl0or of the"heating cham- -ber-andseparating' thedowerportions of the two banksbf-tubes, means for maintaining a supply *of- 'li'q'uid' in {the portion of the *chamber walled offby the baffle andsurrounding the second bank "of tubes, which liquid' -'is*boiled by the hot gases and the steam thus generated flows over the =bafiie-and evolves-vapors fromthe solution in the first bank or tubes; means for withdrawing from the evaporator the vapors thus evolved, and me'ans for withdrawing-from the chamber the condensate from the steam.

"4.- In a 'unitaryevaporatorstructure, the combination of ashell, sp-ace'd'apart upper and lower 5 tube sheets mounted in the shell and completing between them a chamber, a bank of tubes extending through the chamber and having their open ends fixed in the tube shets, means for maintaining in said bank of tubes a supply of the solution to be evaporated, a second bank of tubes extending through the chamber and having their ends fixed in the tube sheets, a partition in said chamber extending upwardly therein and partially separating the respective portions of the chamber through which the two banks of tubes extend, thus providing access between the two portions of the chamber in the upper portion of the latter, means for maintaining a supply of a liquid to the portion of the chamber through which the second. bank of tubes extend, means for passing hot gases through the second bank of tubes to boil said liquid the steam thus generated passing to the portion of the chamber through JOHN E. POTTHARST, JR.

REFERENCES CITED The foliowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,059,481 Maslin Apr. 22, 1913 1.623.941 Sebaid Apr. 5, 1927 1,864,349 Govers June 21, 1932 2,072,713 Folmsbee et a1 Mar. 2, 1937 

